ID'ING
UNDERWATER
GRASSES
ID Tips and Tricks
Leaf Arrangement
Leaf arrangement is a great way to identify plants. Here are common leaf arrangements:
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Basal: Leaves come from base of plant
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Alternate: Leaves come from stem one at a time, alternating sides
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Whorled: Leaves come from stem three or more at one location
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Opposite: Leaves come from stem two at a time from one location on opposite sides
Leaf Edges
Leaves come in many different sizes and shapes, and have different edges. Common margins include:
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Smooth
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Toothed
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Lobed
Learn more about plant identification tips at the beginning of the Delaware Wetland Plant Field Guide.
Flowers and Seeds
During reproductive season, most species will put out flowers, later turning into seed pods. This often occurs late spring- early October, depending on the species. The presence of flowers and/or seeds will help assist in identifying to the species level most of the time.
Macroalgae: Photo credit: Delaware Center for the Inland Bays
SAV vs. Macroalgae
Submerged aquatic vegetation (SAV) are underwater plants that have roots, stems, and leaves, and they anchor themselves in the soil at the bottom. SAV needs sunlight to grow, so it is found in shallow, clear water. These plants also produce flowers and seeds, making them different from algae.
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Macroalgae, often called seaweed, are plant-like organisms also found underwater. They are different from SAV in that they don't have roots or true leaves, and reproduce via spores. They attach to surfaces like rocks, pilings, and SAV leaves or drift freely in the water. They come in three main types, named for their colors: green, red, and brown. These organisms are important because they produce energy through photosynthesis, making them a key part of the food chain, however in waters that have excess nutrients they can become a problem. Click here for more information about macroalgae in Delaware.
Common Delaware Species
Delaware’s waters are home to a variety of submerged aquatic vegetation (SAV) species. Some of these plants are native, meaning they naturally grow in this region and play an important role in supporting local ecosystems. Others are non-native, which means they were introduced from outside the area, often through human activity. Some non-native species are invasive, spreading quickly and outcompeting native plants for space, sunlight, and nutrients. This can harm local wildlife and disrupt the balance of the ecosystem. Non-native plants are managed by the state's Division of Fish and Wildlife.
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Non-native plants can arrive in several ways, such as being accidentally introduced by boats or through the release of aquarium plants into waterways. To help protect Delaware’s aquatic ecosystems, it’s important to properly dispose of aquarium plants—never dump them into natural bodies of water. By being mindful, we can help keep native plant populations healthy and thriving.
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